Multipath TCP (MPTCP) is a new modification of TCP protocol which enables a client to transfer data over multiple paths simultaneously under a single TCP connection, for improved throughput and fault resilience. However, MPTCP is susceptible to some major drawbacks when applied in a wireless network. We found several cases where, despite improving individual MPTCP clients throughput, MPTCP reduces the capacity of the overall wireless network due to the mac level fairness and contention-based access schemes. Additionally, even if the bandwidth improves, employing Multipath TCP (MPTCP) in wireless networks can be energy inecient due to additional energy consumption by multiple interfaces. This creates a dilemma between bandwidth improvement and energy efficiency. This thesis research aims to solve these important issues for MPTCP in the wireless environment. We analyzed the root cause of these drawbacks and identified instances where they can arise. Two novel schemes denoted MPWiFi and kMPTCP, are developed to solve the bandwidth degradation and energy efficiency issues respectively, while maintaining the promised benefitts of MPTCP. The MPWiFi assigns dierent priorities to the subflows and aggressively suppresses some of them based on some design logic. Similarly, kMPTCP adds an additional multipath subflow only if the bandwidth requirement can't be fulllled by single path and the new subflow meets the data rate and signal strength condition. Moreover, kMPTCP keeps additional subflows as long as the signal strength remains in good range and this subflow remain mandatory to provide the necessary bandwidth to the application. These two schemes have been implemented along with Linux Kernel MPTCP implementation. Extensive real-world deployment and NS3 simulation show that the proposed schemes can eectively alleviate the adverse impacts of the MPTCP based multipath access in Wireless networks.

Ingeniero Civil Eléctrico / Entel S.A., la mayor empresa de telecomunicaciones móviles de Chile, requería evaluar el impacto que tendría la incorporación del servicio Voice Over LTE (VoLTE) en su red 4G de datos, en Santiago, con el fin de estimar la inversión requerida en caso de que existiera disminución de cobertura del servicio. Dado lo anterior, el objetivo del presente trabajo de título se enfocó en determinar el área de cobertura que tendrá la actual red 4G de Entel al incorporar el servicio VoLTE. Para llevar a cabo esta tarea se diseñó un Link Budget de VoLTE, el cual se utilizó posteriormente para determinar los puntos de corte en simulaciones que se realizaron en el programa Mentum Planet. De esta forma, se comparó la cobertura de la red de datos (Best Effort) con la cobertura VoLTE. La metodología utilizada en el desarrollo de la presente memoria comprendió la investigación y el análisis de redes móviles LTE, desarrollando y plasmando en el segundo capítulo, una base teórica que permite un amplio y fácil entendimiento de éstas para cualquier persona. Posteriormente, comprendió el diseñó del Link Budget de VoLTE, el cuál fue generado en un documento Excel, otorgando de esta forma una herramienta sencilla y útil al área de optimización de redes de acceso de Entel. El trabajo concluyó con la realización de sets de simulaciones en el programa solicitado, con lo que se obtuvo los porcentajes de cobertura asociados tanto a la red Best Effort como al servicio VoLTE, para las bandas de frecuencia de 2600 MHz y 700 MHz. Entre los principales resultados del presente trabajo, cabe destacar: 1. Disminución aproximada de un 7.5% de cobertura para el servicio VoLTE en comparación a la cobertura del servicio de datos Fourth Generation of Wireless Telephone Technology (4G), para la banda 2600 MHz, considerando Reference Signal Received Power (RSRP) de corte sin fading. 2. Disminución aproximada de un 19% de cobertura para el servicio VoLTE en comparación a la cobertura del servicio de datos 4G, para la banda 700 MHz, considerando RSRP de corte sin fading. 3. Se confirma la importancia del feature TTI Bundling para mejorar la cobertura del enlace ascendente, estableciendo una mejora entre un 20 y un 25% en la cobertura. Como consecuencia final, el presente trabajo entrega a Entel una cuantificación de la cobertura esperada, así como un conjunto de recomendaciones para la implementación del servicio VoLTE, y de ésta forma, pasar a la etapa de evaluación económica para la implementación definitiva del proyecto.

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2015. / Submitted by Raquel Viana (raquelviana@bce.unb.br) on 2015-11-13T18:01:35Z No. of bitstreams: 1 2015_CarolinaAzevedoGuedesFerreira.pdf: 10331070 bytes, checksum: dd53427acde37fa94046e004a4d60e3e (MD5) / Approved for entry into archive by Marília Freitas(marilia@bce.unb.br) on 2015-12-20T15:31:10Z (GMT) No. of bitstreams: 1 2015_CarolinaAzevedoGuedesFerreira.pdf: 10331070 bytes, checksum: dd53427acde37fa94046e004a4d60e3e (MD5) / Made available in DSpace on 2015-12-20T15:31:10Z (GMT). No. of bitstreams: 1 2015_CarolinaAzevedoGuedesFerreira.pdf: 10331070 bytes, checksum: dd53427acde37fa94046e004a4d60e3e (MD5) / Este trabalho apresenta uma investigação prática da modelagem estatística de canais sem fio utilizando a faixa de frequência de 450 MHz com aplicação em futuras redes celulares LTE no Distrito Federal. Estatísticas de primeira e de segunda ordens, tais como PDF, CDF e função de autocorrelação dos modelos de desvanecimento α-μ, Nakagami-m, Rice e Rayleigh, são confrontadas entre si e com os dados experimentais coletados em ambientes do cerrado brasileiro. Os resultados mostram um excelente desempenho da distribuição generalizada α-μ, na qual apresentou o melhor ajuste aos dados experimentais, tanto nas estatísticas de primeira quanto nas de segunda ordens. Além disso, foram realizadas predições de cobertura para o sistema 4G LTE na faixa de 450 MHz para ambientes externos e internos em áreas rurais e suburbanas do Distrito Federal com a finalidade principal de investigar a utilização da tecnologia LTE na faixa de frequência de 450MHz para estas áreas. / This work presents a practical investigation of the statistical modeling of wireless channels using the frequency range 450 MHz with application in future cellular networks LTE in the Distrito Federal. First and second orders statistics, such as PDF, CDF and autocorrelation function of α-μ fading models, Nakagami-m, Rice and Rayleigh, are confronted with each other and with the experimental data collected in the Brazilian cerrado environments. The results show an excellent performance of the α-μ widespread distribution, which presented the best fit to the experimental data, both in the first statistics as the second orders. In addition, coverage predictions were made for the 4G LTE system in the 450 MHz band for external and internal environments in rural and suburban areas of the Federal District for the primary purpose of investigating the use of LTE technology in the 450MHz frequency range for these areas. / This work presents a practical investigation of the statistical modeling of wireless channels using the frequency range 450 MHz with application in future cellular networks LTE in the Distrito Federal. First and second orders statistics, such as PDF, CDF and autocorrelation function of α-μ fading models, Nakagami-m, Rice and Rayleigh, are confronted with each other and with the experimental data collected in the Brazilian cerrado environments. The results show an excellent performance of the α-μ widespread distribution, which presented the best fit to the experimental data, both in the first statistics as the second orders. In addition, coverage predictions were made for the 4G LTE system in the 450 MHz band for external and internal environments in rural and suburban areas of the Federal District for the primary purpose of investigating the use of LTE technology in the 450MHz frequency range for these areas.

abstract: Small wireless cells have the potential to overcome bottlenecks in wireless access through the sharing of spectrum resources. A novel access backhaul network architecture based on a Smart Gateway (Sm-GW) between the small cell base stations, e.g., LTE eNBs, and the conventional backhaul gateways, e.g., LTE Servicing/Packet Gateways (S/P-GWs) has been introduced to address the bottleneck. The Sm-GW flexibly schedules uplink transmissions for the eNBs. Based on software defined networking (SDN) a management mechanism that allows multiple operator to flexibly inter-operate via multiple Sm-GWs with a multitude of small cells has been proposed. This dissertation also comprehensively survey the studies that examine the SDN paradigm in optical networks. Along with the PHY functional split improvements, the performance of Distributed Converged Cable Access Platform (DCCAP) in the cable architectures especially for the Remote-PHY and Remote-MACPHY nodes has been evaluated. In the PHY functional split, in addition to the re-use of infrastructure with a common FFT module for multiple technologies, a novel cross functional split interaction to cache the repetitive QAM symbols across time at the remote node to reduce the transmission rate requirement of the fronthaul link has been proposed. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2017

A grande popularidade dos dispositivos móveis que provêm acesso ubíquo à Internet de banda larga, através de redes de rádio, e o volume de tráfego gerado por estes dispositivos estão aumentando a cada ano. Além disso, vem ampliando consideravelmente a frequência com que usuários de dispositivos móveis estão usando serviços baseados na Web. Alguns destes usuários podem estar acessando serviços que precisam de transmissão contínua como, por exemplo, vídeos interativos, outros podem estar apenas lendo e-mails, o que não exige um fluxo contínuo de dados. Mais do que isso, usuários com altos níveis de sinal podem atingir melhores taxas de transferência do que os com níveis menores. Portanto, encontrar a melhor relação entre os usuários que estão acessando serviços sensíveis ao atraso e aqueles que maximizam a taxa de transferência, e ainda ser justo na transmissão, é um relevante desafio para o escalonamento dos recursos de uma rede sem fio. Embora as pesquisas de escalonamento de recursos em redes sem fio tenham evoluído neste sentido, o recente aumento do volume de tráfego mencionado pode levar a uma sobrecarga no sistema, comprometendo o escalonamento. A fim de enfrentar estes desafios, o Orthogonal Frequency Division Multiple Access (OFDMA), tecnologia fundamental para o acesso múltiplo em redes de quarta geração, tem sido considerado também para ser utilizado na próxima geração de rádios móveis. Para implementar um serviço efetivo aos usuários, requisitos, tais como, altas taxas de transferência, tolerância baixa ao atraso, minimização da perda de pacotes e maximização da justiça no escalonamento, devem somar-se à característica, de alta densidade de usuários, que surgiu após o advento da popularização dos dispositivos móveis. Portanto, novas estratégias de escalonamento devem ser idealizadas. Nesta dissertação, deu-se um passo além na proposição de um escalonador para as redes móveis de próxima geração, que busca melhorar a relação entre taxa de transferência e atraso, consequentemente, levando a maiores índices de justiça no escalonamento resultante. O escalonador foi especialmente desenvolvido para lidar com altas densidades de usuários, inerentes às redes modernas, e as redes LTE foram utilizadas como caso de estudo. Desta forma, um novo escalonador ótimo que considera provisão dos requisitos acima mencionados, é modelado. Além disso, uma nova heurística parametrizável, baseada na qualidade do canal do usuário, no atraso permitido por cada serviço e na justiça do escalonamento é proposta, a fim de lidar com cenários sobrecarregados. Resultados demonstram que a abordagem de escalonamento proposta leva a uma taxa de transferência apenas 7,5% menor que os valores ótimos, com 25% a menos de perda de pacotes em cenários sobrecarregados. O modelo também garante que o escalonamento resultante seja pelo menos 0,91 na escala do índice de justiça de Jain. Finalmente, os resultados mostram uma melhor relação entre a eficiência espectral e as métricas de QoS. / The huge popularity of mobile devices that provides a ubiquitous Internet broadband access via radio networks and the volume of traffic generated by these devices in the base stations are increasing every year. Furthermore, the frequency which, mobile users are using web-based services, is increasing, requiring high transfer rates such as transmission of interactive videos. These factors have become the main challenges for the scheduling of radio resources. In order to meet these challenges, the Orthogonal Frequency Division Multiple Access (OFDMA), a key technology for multiple access in fourth generation networks, has also been considered for use in next-generation mobile radios. To implement an effective service to users, requirements such as high transfer rates, lower delay tolerance, minimum packet loss and maximum scheduling fairness, should be added to the requirements that emerged after the advent of the popularity of mobile devices. Therefore, new scheduling strategies should be projected. Despite efforts to solve the downlink (DL) scheduling problem on wireless networks, we are not aware of previous attempts that have addressed the above requirements in a single strategy. In this thesis, we took a step further in this direction and still considering the high densities in small cells inherent in modern networks. In additional, we address the radio DL resource scheduling problem for multiple users using LTE networks as a case study. A new optimal scheduler is modeled regarding Quality of Service (QoS) provisioning. In addition, a parameterized heuristic based on user channel quality and service delay is proposed to reach scheduling solutions for overbooked scenarios. Results demonstrate that the proposed scheduling approaches led to a throughput of 7.5% lower than the optimal ones and 25% lower packet losses in overloaded scenarios. Our model also ensures that the resultant scheduling is at least as fair as 0.91 in Jain fairness index. Additionally, the obtained results show a reasonable trade-off between spectral efficiency and QoS metrics.

abstract: LTE-Advanced networks employ random access based on preambles transmitted according to multi-channel slotted Aloha principles. The random access is controlled through a limit <italic>W</italic> on the number of transmission attempts and a timeout period for uniform backoff after a collision. We model the LTE-Advanced random access system by formulating the equilibrium condition for the ratio of the number of requests successful within the permitted number of transmission attempts to those successful in one attempt. We prove that for <italic>W</italic>&le;8 there is only one equilibrium operating point and for <italic>W</italic>&ge;9 there are three operating points if the request load &rho; is between load boundaries &rho;₁ and &rho;₂. We analytically identify these load boundaries as well as the corresponding system operating points. We analyze the throughput and delay of successful requests at the operating points and validate the analytical results through simulations. Further, we generalize the results using a steady-state equilibrium based approach and develop models for single-channel and multi-channel systems, incorporating the barring probability <italic>P<super>B</super></italic>. Ultimately, we identify the de-correlating effect of parameters <italic>O, P<super>B</super>,</italic> and <italic>T_o<super>max</super></italic> and introduce the Poissonization effect due to the backlogged requests in a slot. We investigate the impact of Poissonization on different traffic and conclude this thesis. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2014

The increase in vehicular traffic has created new challenges in determining the behavior of performance of data and safety measures in traffic. Hence, traffic signals on intersection used as cost effective and time saving tools for traffic management in urban areas. But on the other hand the signalized intersections in congested urban areas are the key source of high traffic density and slow traffic. High traffic density causes the slow network traffic data rate between vehicle to vehicle and vehicle to infrastructure. To match up with the emerging technologies, LTE takes the lead with good packet delivery and versatile to changes in the network due to vehicular movements and density. This thesis is about analyzing of LTE implementation based on a road traffic density model. This thesis work is aimed to use probability distribution function to calculate density values and develop a real traffic scenario in LTE network using density values. In order to analyze the traffic behavior, Aimsun simulator software has been used to represent the real situation of traffic density on a model intersection. For a realistic traffic density model field measurement were used for collection of input data. After calibration and validation process, a close to realty results extracted and used a logistic curve of probability distribution function to find out the density situation on each part of intersection. Similar traffic scenarios were implemented on MATLAB based LTE system level simulator. Results were concluded with the whole traffic scenario of 90 seconds and calculating the throughput at every traffic signal time and section. It is quite evident from the results that LTE system adopts the change of traffic behavior with dynamic nature and allocates more bandwidth where it is more needed.

Den nya generationens mobila nätverksteknologi som Long Term Evolution (LTE) blir allt mer komplex med avseende på struktur och kommunikation. Allt viktigare blir utbildningsverktyg som beskriver komponenter och kommunikationsstrukturer inom denna teknologi. Detta ställer samtidigt krav på att verktyget håller en hög nivå av användbarhet. I denna studie genomfördes en användbarhetsutvärdering av LTE-simuleringsmjukvaran SimuLTE. Studien utfördes genom en utvärdering med 12 målbaserade, heltäckande scenarion som nio deltagare med teknisk bakgrund fick genomföra. De målbaserade scenarierna baserades på problemområden som identifierats med hjälp av en heuristisk utvärdering av systemet. Utvärderingsinstrumentet System Usability Scale (SuS) användes för att skatta användarnas subjektiva värdering av SimuLTEs användbarhet. Utvärderingstillfällena avslutades med inviduella intervjuer med deltagarna. Resultatet från studien indikerade att SimuLTE kan vara ett lämpligt undervisningsverktyg. Deltagarna kunde slutföra de målbaserade scenarierna inom utsatta tidsramar, vilket indikerar att verktyget lämpar sig för målgruppen. Systemet erhöll en SuS-poäng på 68 poäng, vilket kan anses vara acceptabelt med tanke på den korta introduktionen till systemet. Intervjuerna visade att flertalet av deltagarna ställde sig positiva till den visuella representationen av LTE-strukturen. Identifierade brister i systemet som bör åtgärdas gäller främst systemstatus och återkoppling.

Ingeniero Civil Eléctrico / El creciente avance de las telecomunicaciones móviles nos permite hoy en día, no tan solo comunicarnos con quien deseamos de una manera fácil y rápida, sino que también nos entrega la posibilidad de descargar archivos, música y videos a través de nuevas generaciones de dispositivos móviles, liderados principalmente por los teléfonos inteligentes o smartphones. Actualmente la penetración de la telefonía móvil alcanza un 140% y con ello se acrecienta la demanda de servicios que utilizan un mayor ancho de banda, lo que congestiona la red y hace que los usuarios perciban una calidad de servicio deteriorada. Los operadores de telecomunicaciones responden a la necesidad del usuario, tanto de mayores velocidades de datos como de una mejor calidad de servicio, con la incorporación de una nueva y mejor tecnología de acceso a internet, denominada Long Term Evolution (LTE), la cual alcanzaría velocidad hasta 10 veces mayores que sus predecesoras, además de contar con bajos tiempos de latencia. El presente Trabajo de Título, tiene como motivación satisfacer la necesidad de capacitación existente, tanto en la industria como en los centros de estudio, enfocando el contenido de un curso, tanto teórico como práctico, hacia el análisis de la Calidad de Servicio (QoS, Quality of Service) percibida por los usuarios de los servicios de Banda Ancha Móvil (BAM) actualmente montados sobre redes 3G y sobre las futuras redes LTE. El objetivo general del Trabajo de Título es desarrollar un curso sobre calidad de servicio en Redes 3G y LTE, compuesto por una parte teórica y una parte práctica o de laboratorio. Para lograr el objetivo planteado, se diseña una metodología docente para la parte teórica del curso, la cual consiste en la confección de un material docente basado en el diseño y construcción de cursos universitarios, mientras que para la metodología de los prototipos de prueba, se diseñan e implementan una serie de pruebas de laboratorio, que ejemplifican como diversos factores de red y condiciones de usuario afectan la QoS percibida por el usuario de servicios BAM tanto para redes 3G como para LTE. Los prototipos de prueba se implementan bajo la red de un ISP en el caso 3G y bajo la red de un laboratorio en el caso LTE. El resultado del trabajo es el material complementario para un curso, compuesto en su parte teórica por nueve capítulos, y en su parte práctica por nueve experiencias de laboratorio basadas en prototipos de prueba diseñados e implementados. Cada capítulo se materializa en un conjunto de diapositivas a modo de material docente, mientras que, por otro lado, se confecciona una guía de laboratorio con los prototipos de prueba detallados paso a paso. Las pruebas de laboratorio fueron validadas a través de la obtención de mediciones de throughput, en condiciones de red simuladas, observándose una disminución de la QoS acorde con los resultados teóricos. El Trabajo de Título propone como trabajos futuros la realización de más prototipos de prueba, usar los prototipos descritos en esta memoria, en otras tecnologías de acceso o en la futura red LTE y por último la realización de las pruebas a través de un enlace internacional. La memoria de Título presenta una propuesta atractiva para un curso que abarca temáticas contingentes y de interés tanto para los Operadores de Telecomunicaciones como para los estudiantes del DIE de la Universidad de Chile, estableciendo metodologías de medición con proyecciones en el plano investigativo principalmente para redes LTE.

Future generation cellular networks are expected to deliver an omnipresent broadband access network for an endlessly increasing number of subscribers. Long term Evolution (LTE) represents a significant milestone towards wireless networks known as 4G cellular networks. A key feature of LTE is the implementation of enhanced Radio Resource Management (RRM) mechanism to improve the system performance. The structure of LTE networks was simplified by diminishing the number of the nodes of the core network. Also, the design of the radio protocol architecture is quite unique. In order to achieve high data rate in LTE, 3rd Generation Partnership Project (3GPP) has selected Orthogonal Frequency Division Multiplexing (OFDM) as an appropriate scheme in terms of downlinks. However, the proper scheme for an uplink is the Single-Carrier Frequency Domain Multiple Access due to the peak-to-average-power-ratio (PAPR) constraint. LTE packet scheduling plays a primary role as part of RRM to improve the system’s data rate as well as supporting various QoS requirements of mobile services. The major function of the LTE packet scheduler is to assign Physical Resource Blocks (PRBs) to mobile User Equipment (UE). In our work, we formed a proposed packet scheduler algorithm. The proposed scheduler algorithm acts based on the number of UEs attached to the eNodeB. To evaluate the proposed scheduler algorithm, we assumed two different scenarios based on a number of UEs. When the number of UE is lower than the number of PRBs, the UEs with highest Channel Quality Indicator (CQI) will be assigned PRBs. Otherwise, the scheduler will assign PRBs based on a given proportional fairness metric. The eNodeB’s throughput is increased when the proposed algorithm was implemented.